The present invention relates to a new and improved turbine engine component and the method by which it is made. Specifically, the present invention relates to a turbine engine component having a plurality of airfoils disposed in an annular array between inner and outer shroud rings.
A method of making a turbine engine component having an annular array of airfoils disposed between inner and outer shroud rings is disclosed in U.S. Pat. No. 4,728,258, issued Mar. 1, 1988 and entitled "Turbine Engine Component and Method of Making the Same". Slip joints are provided between the airfoils and a shroud ring to accommodate thermal expansion of the airfoils relative to the shroud ring. When the airfoils are heated to a temperature above the temperature of the shroud ring, thermal expansion of the airfoils causes the slip joints to open.
The turbine engine component design disclosed in the aforementioned U.S. Pat. No. 4,728,258 is generally satisfactory. However, the design of the shroud ring is relatively simplistic in that it has no mounting flanges or rails. The strength of the shroud ring tends to be minimized due to the presence of the openings in the shroud ring to accommodate the slip joints. Thus, the strength of the shroud ring is determined by relatively small sections of material which are disposed adjacent to the leading and trailing end portions of the airfoils.
It has previously been suggested that a turbine engine component having an annular array of airfoils disposed between inner and outer shroud rings be provided with a rail which facilitates mounting of the shroud ring in an engine and which strengthens the shroud ring. However, if the rail is to strengthen the shroud ring adequately, the rail may extend across the ends of the airfoils. In such a shroud ring design, the rail would interfere with expansion of the airfoils.